Electromechanical speed governor



Sept 23, 1952 c. P. MOLYNEUX 2,611,352

ELECTROMECHANICAL SPEED GOVERNOR y Filed Jan. 17, 1950 ATTORNEYS Patented Sept. 23, 1952 ELECTROMECHANICAL SPEED GOVERNOR Cecil Patrick Molyneux, Hampton Bays, N. Y., as-

signor to Molyneux and Aspinwall, Inc., Long Island City, N. Y., a corporation of New York Application January 17, 1950, Serial No. 139,106

11 Claims. (Cl. 12S-102) My invention relates to improvements in speed governors of the electromechanical type for regulating or limiting the speed of internal combustion engines, motor vehicles and other mechanisms, and for synchronizing the speeds of two or more mechanisms.

My improved speed governor is adapted to overcome the disadvantages involved in the manufacture, installation .and use of the present types of governors. For example, the well-known type of fly-ball governor used on engines of various types. and on trucks and other vehicles, is expensive to make and requires special structural arrangements for installation. Furthermore, governors of this type are not sufciently accurate and reliable for present requirements.

The primary object of the present invention is, therefore, to provide an improved apparatus for governing the speed of an engine or other mechanisms which is relatively inexpensive to manufacture, which may be installed in a relatively short time, and which may be readily combined with the standard equipment of an engine or other mechanism to be controlled.

A further object of the invention is to provide an improved governor which will effect a close control of the speed of the engine or other mechanism to be governed or controlled.

Trucks and buses, powered by internal combust-ion engines, provide a large iield in which -governors are now used to some extent and in which their use to a greater extent is highly desirable. These and other vehicles and mechanisms driven by internal combustion engines have ignition systems in which a current is created having frequencies proportional to the speed of the engine. According to my invention, I make use of this available relationship, and provide a control unit including a tuned reed 4having a response frequency set at or correa mechanism is controlled by subjecting a tuned reed to forces tending to vibrate it at a frequency bearing a selected relation to the speed of the mechanism and utilizing the increased amplitude of movement of the reed when said frequency accords with that of thel reed to effect control of Y the speed of the mechanism. The governor may comprise avunit connected up to actuate a suitable control such as the butterfly valve of an engine, or to open the battery circuit to the igni- .zztion coil-of the ignition system AofA an engine.

The governor unit advantageously includes means for eliminating or reducing reed resonance response at sub-multiples of the governing speed. In a preferred construction, the mounting for the tuned reed also carries at least one additional reed which is tuned to the sub-harmonic frequency which would be likely to affect the governing reed, the additional reed being adapted to vibrate at maximum amplitude at this unwanted frequency, and thereby reduce the response of the tuned reed to that frequency.

Additional features of my invention are described in detail hereinafter in connection with illustrative embodiments of governor units associated with the ignition circuits of internal combustion engines. These embodiments are shown in the accompanying drawings forming a part of this application and in which: I

Fig. 1 is a broken diagrammatic view of one embodiment of my invention shown in association with a conventional ignition system of an internal combustion engine.

Fig. 2 is a broken diagrammatic view showing a modication of a portion of the governor unit shown in Fig. 1.

Fig. 3 is a view similar to thatof Fig. 1 showing a modified form of construction and arrangement.

Referring to Fig. 1 of the drawings, the invention is illustrated in connection with conventional elements of an ignition system of an internal combustion engine. These elements comprise a battery IU, an ignition switch I I, a distributor in- Clllding a Contact breaker I2 and a current distributor I4, the moving elements of Awhich are carried on a shaft I6 driven by the engine, and a spark coil l1 having primary and secondary windings I8 and I9 respectively. The contact breaker I2 includes contacts 2|, one of which is actuated by the breaker and the other of which is grounded as shown.

The battery IU,shown grounded in a conventional manner, is connected through the switch II to one terminal of the primary winding I8 of the spark coil I1. The other terminal of the winding I8 is connected to the secondary Winding I 9, to the movable contact of the contact breaker switch 2l at a point 25, and is connected through a condenser 22 to ground. The e`nd of the secondary winding I9, opposite that connected to the winding I8, is connected up for the supply of current to the ignition distributor I4 from which high tension current flows to the six spark l plugs 23, of conventional design, having the usual grounded connections shown Y diagrammatically provided with an armature 39.

at 24. The ground connections shown in the drawings are made to the body or frame of the engine as in conventional practice.

The governor mechanism as shown in Fig. 1, comprises a frequency sensing device 26 electrically connected into the ignition circuit described above and to a control actuating means. 'Ihe device shown generally at 26 includes a tuned metal reed 21 set in a mounting between a pair of similar contact arms 28, all insulated with respect to each other by layers of insulation i 29. The reed 21 is provided with a pair of adjacent contacts mounted opposite and normally spaced from respective cooperating contacts on the arms 28. The upper end of the reed 21 is An auxiliary reed 3| having an armature at its upper end and somewhat shorter than the reed 21, is secured to the base assembly in parallel with the reed 21. The reed 3| has a selected tuned frequency which is a sub-harmonic of the frequency of the reed 21.

Ametal supporting arm 32 is fastened to the base assembly including the layers of insulation 29 and at its upper end carries an electromagnet 33 having a fixed core 34 which may also be used for securing the electromagnet to the support 32 in a position above the'upper ends of the reeds 21 and 3|. The electromagnet 33 includes a suitablewinding, one terminal of which is electrically connected bya wire 35 to the movable arm of the contact breaker switch 2| at the point 20, and thereby also connected to the lower end of the primary winding I8.` The other terminal of the coilof the electromagnet 33 is electrically connected through a wire 3:5 at a point 31 to the battery current'supply line leading through the ignition switch The wire 3S is also electrically connected by wires 38V for the supply of current to the contaetarms 28.

The lower end of theY metal reed 21 is electrically connected by a wire im for the supply of current to a control actuating means, which, in the example as shown in Fig. l, comprises a solenoid 4|. The currentoutlet of the coil of the solenoid 4I is wired to Ya ground connection and to the current'lead 4|) through a suitable condenser 42 which is provided for the purpose of reducing sparking between the contacts of the Vreed 21 and the contact arms 28.

Solenoid 4| is provided with a movable armature'43 carrying a rack 44 which engages a pinion 45 carried on the shaft of a butterfly valve control 46, arranged in the engine fuel intake line 41. The butterfly valve 46 may be that actuated by the usual engine throttle or a valve separately arranged in the fuel intake of the engine.

The operation of the apparatus shown in Fig. 1 may be described by assuming, for example, that the ignition system is that of an engine having six cylinders represented by the six spark plugs 23. After the ignition switch is closed and the engine started, the lcontact breaker l2 alternately opens and closes the contact switch 2| at a rate corresponding to the speed of the engine,

Vsince the shaft I6 is driven directly by the en- Y gine. q A pulsating `current is therefore produced having a frequency which varies directly with the speed of the engine.

Current flows from the point 31 through the connecting wire 36, the coil of the electromagnet 33 and the wire 35, at the frequency of the switch 2|, to actuate the electromagnet at the same frequency. The electromagnet v33 in turn acts upon the reeds 21 and 3|. but if the frequency of the electromagnet at a given speed of the engine is not close to that of the tuned frequency of either of the reeds, they will not vibrate appreciably. When, as the engine speed increases, the frequency of the electromagnet 33 reaches that of the tuned reed 3|, this reed will vibrate, but, since it is not a control reed, it merely prevents thev vibration of the reed 21 at a sub-harmonic of the tuned frequency of the latter.

As the speedrof the engine is further increased the frequency of the electromagnet 33 eventually reaches that of the tuned reed 21 so that it is caused to vibrate and thereby effect the closing of the contacts between it and the contact arms 28, thus permitting current to flow through the wires 38 and lill to energize the solenoid 4|. The solenoid 4| in turn actuates the means for moving the butterfly valve 46 toward closed position, thereby preventing operation of the engine above a speed corresponding to the tuned frequency of the reed 2.1. x Y

The operation ofthe control'apparatus described above in connection with Fig. 1may be illustrated more specifically in connection with a particular engine speed. Assume, for example, that it is desirable to limit the speed of asixcylinder, four-cycle automotive engine to 3,000 R. P. M., corresponding, for example, to aparticular speed of the automotive vehicle.` Since the engine is a four-cycle engine, the contact breaker |2 will kactuate the switch 2l, oncefor every two strokes for each cylinder, which, in the case of the six-cylinder engine will be three times per revolutionY This value times 53,000 R. P. M. for the engine, gives 9,090` electrical impulses per minute in the electromagnet 33, or impulses per second. If the natural or set frequency of the tuned reed 21 is 'selected or adjusted to 150 per second', the tuned reed 3| advantageously has a tuned frequency of half vthat frequency, or 75, so that it would prevent the vibration of the reed 21 at this troublesome subharmonic frequency.

The flexible reed 2 in the example referred to, may have a tendency toV vibrate to 'some extent at various sub-harmonic frequencies of its 150 per second, but the auxiliary reed 3|, which acts as a mechanical shunt; prevents its` vibration to an extent sufcient to close a ycircu'it'with the contact arms 28. l

It will beunderstood that the solenoid 4I may be used to actuate any suitable engine control other than the valve 4E, as described above. Where the actuating means shown in Fig.' l is used, the armature A3 in solenoid di is advantageously arranged as a close-fitting plunger in the solenoid, so as to obtain dash-pot action, and thereby provide a mechanical time delay means to prevent the reed 21 from passing through its natural frequency by the rapid acceleration of the engine at speeds close to the control speed.

The solenoid 13| may be replaced or supplemented as a motive means by any other suitable control actuator. Such a modified motive means is illustrated in Fig. 2 for actuating 'a butterfly valve Mib in a fuel intake line 41h. In this apparatus current supplied from the reed 21 upon its vibration at' its tuned frequency is conducted through a wire lb and the windingfof Va small solenoid Mb, from which the current outletis grounded, as shown, and connected to the Wire 4Gb through a condenser 42h. In this' case, the

mounted inv a suction line 49-leading from the engine intake -pipe 41h and connected into a small cylinderll. A piston 5I in the cylinder 50 and normally biased upwardly by a light spring, as shown, is connected to a rack 44h which meshes with a pinion 45h on the butteriiy valve 46h.

When the selected engine speed is reached and vibration of the tuned flexible reed 21 supplies current through the wire 40h, the needle valve 48 is opened, so that the suction in the intake manifold and the fuel supply pipe 47h, is applied in cylinder 50.; This suction moves the piston to actuate the butterfly valve 4Gb toward closed position, thereby reducing the speed of the enigine. As' the engine speed is reduced the valve valve 46h;

The modified form of apparatus shown in Fig.

of the drawings is one inwhich the frequencyv sensing reed structure is combined directly with' an engine ignition coil, and in which the means responsive to the frequency sensing device is ar.:k

ranged to cut off the supply of current to the ignition system of the engine. In Fig. 3, an igni'l tion coil casing A, and its plastic cap B, are shown ized as an over-speed control adapted to prevent an engine from running :away should a governor of any type fail. Assuming, for example, that an 'y internal combustion engine'is driving a generator 'l5 48 returns to its seat and the spring in the cylinder 50 returns the piston and buttery valve to the normal positions shown. This form of mecha-1v nlsm reduces the current requirements of tlie governorand provides great torque to move the 53 through a lead 54 with the ignition distributor f' |4a. The primary winding 55 is connected through a terminal 56 and a wire 51 to the battery lIlla. An ignition switch 58 and an ammeter 59 rThe contact arms 28a are connected by a wire 64 to the lower end of the primary winding 55 at the point 65, for the supply of current through the contact arms 28a to a pair of oppositely mounted contact arms 66 arranged on the lower portion of the' tuned metal reed 21a.

The ignition coil shown in Fig. 3 includes a softiron core s1 within the windings 53 and 55.

This core vhas Ta tapered lower end, and the upperl end of the tuned flexible reed 21a with its armature 30a is mounted adjacent thereto within the magnetic influence of the iron core.r

When the frequency of the magnetic impulses produced in the core B1 by the coil 55 and V:the contact breaker |2a reaches that of the natural frequency of the tuned reed 21a, the latterwill vibrate with sufficient amplitude to close a circuit between the contact arms 66 and 28a, to in turn supply current from the lower end of the vreed 21a to the solenoid 4Ia. The energization ofgthe solenoid 4 la opens the' switch 6| thereby opening the battery circuit through the ignition coil to the contactbrfeaker and stopping the engine.

The arrangement shown in Fig. 3 may be utilat 1200 R. P. M, and that the reed 21a is tuned to -vibrate at a frequency produced by an engine speed of 1275 or 1300 R. P. M., now, if the engine over-speeds suiiiciently to reach an R. P. M. of

. 1275 or 1300, the reed 21a is vibrated to close the contacts of the arms 28a and 66, thereby energizing the relay circuit and opening the battery circuit to the ignition coil.

A standard relay may be employed to provide the solenoid 4Ia and switch 6l, such relay preferably being of the type having normally closed contacts which are opened when the coil of the solenoid is energized. The relay is also advantageously provided with Ya mechanical lock-out y to prevent the cycling of the control system. and

with a reset button to restart the engine or other prime mover controlled by the governor.

vThe governor apparatus shown in Fig. 3 of the drawings advantageously includes means such as an auxiliary reed arranged like the reed 3| in Fig. 1 for enhancing the selectivity and effectiveness of the tuned control reed 21a. Since such a means is shown in Fig. l, it is not repeated in Fig. 3.

Instead of using an auxiliary reed, other means may be provided for preventing reed resonance response at sub-multiples of the governing speed or frequency. These unwanted frequency responses can be eliminated by making the armatures 30 and 30a of permanent magnetic material or by making the reed itself of such material. In either case the reed is polarized and its response to sub-harmonic frequencies is greatly reduced or eliminated. The response of the tuned reed to sub-harmonic frequencies may also be eliminated by providing an additional winding in the electromagnet 33 which is connected across the battery to provide a steady D. C. magnetizing field which polarizes the electromagnet. While any of these means may be employed, it has been found that the auxiliary reed is a simple and sufliciently effective means for reducing or eliminating the response of the tuned reed 21 or 21a to troublesome sub-harmonic frequencies.

It has been found by experience that the tuned reed-contact arm assembly provides adequate power for energizing the governor actuating means. As the frequency of the iield produced by the` electromagnet 33, or the equivalent means in Fig. 3, approaches and reaches the frequency of the tuned controlling reed 21 or 21a, the frequency of the vibration of the reed does not change materially, but the length of dwell of the reed contacts on contact arms 28 or 28a, increases because of the bending of the reed, due to its iiexibility. This increase in the dwell of the contacts increases the power applied to the control actuating means, such as the solenoid 4I, thereby insuring adequate power to operate the control at the selected maximum speed of the mechanism being controlled by the governor.

The apparatus of the present invention may be utilized for limiting the speed of any mechanism which produces a current suitable as a frequency reference, such as means for producing electric impulses at a rate which varies proportionately with thespeed of the mechanism. The improved apparatus may be used'for controlling the speed of mechanisms which `do not include such means where it is possible to provide means for produc- .aci-mdc ingr electric. impulses atl a 'ratez proportional rifQ thetspeed'of themechanism. Further.' illustrations `of 'mechanisms which may be governed by the apparatus of the present invention include torpedoes, rockets, jet engines and planes, diesel-engines and generators. The fly-.ball governors used on .torpedoes and jet engines are onlyaccurate to within 10%,- so that itis :unsafeito setthe governor for maximum power. On the other hand, the governor of. the present invention will control to within 0.5% of the set value, and if used inplace of these yballY governors, VVwould increase the available horse--powerzbv as much as 140. l f

Torpedoes, jet engines and the like are usually provided` with a lsmall. alternator which canV be used' Aas a frequency reference source for the governor of the present invention. The connec- .tions to. the tachorneter of such engines may also be, used tov provide the frequency reference for the governor.y i 'The speed of a diesel engine may be controlled by mounting a small'commutator on the flexible shaft between vthe tachometer and the engine, and using it; Vto produce the frequency'reference current to operate the governor.v of the present invention.

The governor may also be used to put an electric generator in vphase with a power line. In this adaptation Ithe actuator of the governor operates a relay to connect the generator with .the power line at the instant thergenerator comes into phase with the power line, vThe reeds 21 and 3| are advantageously replaceable in the governor unit so that reeds may bey-inserted havingrthe .desired tuned `frequency I orfthe particularmaximum speed of any prime mover to be governed.

-What 1 claim is; f y A.15A `speed* governor for an internal combustionrrengine having an electric battery and a contact .breaker driven by the engine in circuit with the battery, a tuned reed having axed end and a free end adapted to be vibrated at the natural frequency of the reed, an armature mounted on the free end vof the reed, electric .means adjacent-the armaturefor vproducing a magnetic field acting on thearmature, means including a current lead for supplying current from said circuit of the contact breakerto said electric means at the frequency produced by the contact breaker, a switch associated withv the reed and adapted-to be olosedupon vibration of .the reed at its natural frequenc, vmeans for supplying4 current from therbatteryto one side Y of said switch, means for reducing the speed of .current to the engine distributorwhen said reed is vibrated at its natural frequency. y

3.v A speed governor as claimed in claim 1 in which theengine includes an ignition spark coil having a primary winding in circuit betweenthe Ybattery and contact breaker and in which the speed reducing means includes a normally closed switch .in the circuit between the primary winding and the contact breaker, said power means being voperatively arrangedvto open said switch in yrespense te the vibration of the reed at its natural frequency: ,i

,I dei. a srccdzgcverccr'fcr aainternalccmhustics engine having an electric battery. a spark coil.. a ccntaclfbreaker,` a distributor and ccnnectcrs `ionizing an ignition circuit, a tuned reed having a fixed end and a free end adaptedtc be vibrated at the. natural frequency of the rccdl an armature mounted on the free end vof the reed, the free end of the reed and armature being mounted OppQSite the en d of -the core of the spark coil and subject to the magnetic eld produced by the frequency1 of the current flowing through the coil from the battery', a switchassociated lwith the reed and adaptedto be closed upon vibratien of the reed atitsl natural frequency, means for supplying current from the battery' to one side of said switch. meansforereducingthe speed of the engine including an electric power means, and a current lead.l from the other side of said switch to said electric power means, said reed having a natural frequency corresponding to the frequency of said current flowing through the spark coil at the maximum desired engine speed.r y

. 5,. A speed governor as claimed in'claim 4 characterized by including a control means operatively associated with the core ofthe sparkcoil for preventing reed resonance response at submultiples ofthe natural frequency of the reed, whereby actuation of said switch is prevented except when the reed is vibrated at its natural frequency.

I6. A' frequency responsive control mechanism .comprising a tunedreed adapted to be vibrated at a prees'elected frequency, an electrically-operated means operatively associated with the reed for effecting its vibration at its tunedfrequency, means for supplying electric currentv of variable frequency to said electrically-.operated means, a normally open electric switch associated with the 'reedand Varranged to be closed by the reed when the reed is vibrated at its tuned frequency, means operatively associated with said electricallyoperated means'for preventing vibration of the tuned reed at frequencies other than its tuned frequency to an 'extent sufficient to close said normally open electric switch,`means for supplying electric current to one side of said switch, a control circuit including a relay having open and closed positions and biased to one of said positions, andan electrical connection fromthe other side of said normally open electric switch to said relay for actuating said relay to its other positionwhen -saidnormallyopen electric switch is closed by the vibration ofthe reed at its tuned frequency.v

v 7. A frequency-responsive control mechanism as claimed in claim 6, in which said means opera-.- tively associated with said electrically-operated means comprises a control means.

-8. A frequency-responsive control mechanism as .claimed in claim 6, in which said means operatively associated With said electrically-operated means comprises a permanent magnet armature mounted on the free end of the reed.

9. Afrequency responsive control mechanism as claimed in claim 6, in which said means operatively associated with said electrically-operated means comprises an auxiliary reed mounted adjacent to the tuned reed, said auxiliary reed having a tuned frequency which isa subharmonic of the frequency of said tuned reed, whereby sub'- stantial vibration of said tuned reed in prevented 4at subharmonic frequencies' of its tuned frequency.y i"

10. A speed governorfor an internal combusf --tion enginehaving anignition system including a spark coil, a contact breaker and a distributor driven by the engine, a source of electric current, and electrical connectors forming an ignition circuit fdr the system, said governor comprising a tuned reed having a fixed end and a free end, the reed having a predetermined tuned frequency, an armature mounted on the free end of the reed, electric means mounted adjacent the armature on the free end of the reed for producing a magnetic field adapted to act on the armature to vibrate the reed at said frequency, means including elecl trical connectors for supplying electrical impulses from the circuit of the ignition system to said electric means at the frequency produced by the contact breaker of the ignition system, a normally open switch operatively associated with the reed and adapted to be closed upon vibration of the reed at its tuned frequency during operation of the engine at a predetermined speed, an electrical conductor connected into one side of said switch for conducting electric current thereto, an electrically-operable means for reducing the current supplied to a part of the ignition system when the engine is operated at said predetermined speed to reduce the speed of the engine below said predetermined speed, and an electric conductor connected into the other side of said switch and into said electrically-operable means for effecting its energization, said electricallyoperable means being operatively associated with a portion of the ignition circuit of the ignition system and adapted to reduce the current supplied to said part of the ignition system when said reed is vibrated at its tuned frequency, closes said normally-open switch and energizes s-aid electrically-operable means.

11. A speed governor for limiting the speed of an internal combustion engine having an ignition system including a spark coil, a contact breaker and a distributor driven by the engine, a source of electric current, and electrical connectors forming an ignition circuit for the system, said governor comprising a tuned reed having a fixed end and a free end, the reed having a predetermined tuned frequency, an armature mount- L o ed on the free end of the reed, electric means mounted adjacent the armature on the free end of the reed for producing a magnetic eld adapted 10 to act on the armature to vibrate the reed at said frequency, means including electrical connectors for supplying electrical impulses from the circuit of the ignition system to said electric means at the frequency produced by the contact breaker of the ignition system, a normallyopen switch operatively associated with the reed and adapted to be closed upon vibration of the reed at said tuned frequency during operation of the engine at a predetermined speed, an electrical conductor connected into one side of said switch for conducting electric current thereto, a normally-closed electric switch in the portion of the ignition circuit in which the contact breaker is located, the normally-closed switch being in series circuit with the contact breaker, an electrically-operable means for opening said normally-closed switch, and an electric conductor connected into the other side of said normally-open switch and into said electrically-operable means for efecting its energizaticn, said electrically-operable means being adapted to open said normally-closed switch and cut-off the current to the contact breaker when said reed is vibrated at its tuned frequency, closes said normally-open switch and thereby energizes said electrically-operable means.

CECIL PATRICK MOLYNEUX.

CETED The following references are of record in the nie of this patent:

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